Combustion Chamber Housing and Gas Turbine Equipped Therewith

ABSTRACT

Combustion chamber housing ( 10 ) and gas turbine ( 1 ) outfitted therewith. The combustion chamber housing has a flame tube ( 20 ) and a casing tube ( 30 ) which surrounds the flame tube and which has a plurality of openings ( 31 ) in its wall through which air outwardly streaming upon the casing tube can penetrate radially into an intermediate space ( 40 ) formed between the casing tube and flame tube. The invention ensures a more uniform distribution of the in-flowing air around the flame tube. This is achieved inter alia in that a plurality of guide ribs ( 50 ) are provided which are arranged in the intermediate space so as to be distributed around the circumference of the two tubes and which extend in each instance radially between the casing tube and flame tube and parallel to a longitudinal direction (LR) of the two tubes so that the intermediate space is divided by the guide ribs into a plurality of longitudinal channels ( 41 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a U.S. national stage of application No. PCT/EP2012/056878, filed on 16 Apr. 2012, which claims priority to the German Application No.: 10 2011 007562.3, filed: 18 Apr. 2011, the content of both incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is directed to a combustion chamber housing and to a gas turbine outfitted with a combustion chamber housing.

2. Prior Art

A known combustion chamber housing and a gas turbine is described in DE 10 2006 042 124 A1. The combustion chamber housing described in that document is a component part of a combustion chamber of the gas turbine and has a flame tube and a casing tube or baffle, which surrounds the flame tube and which has a plurality of openings in its wall through which compressed air outwardly streaming upon the casing tube can penetrate radially into an intermediate space formed between the casing tube and the flame tube.

Combustion chambers are constructed as individual modules, as annularly arranged individual burners or as annular combustion chambers. With the exception of annular combustion chambers, these types of combustion chambers always have an inner cylindrical flame tube.

In a gas turbine of the type mentioned above, the combustion air is initially sucked in from the atmosphere and then compressed in a compressor of a gas generator. The compressor can be of the radial or axial type. The combustion air is then sharply deflected in the combustion chamber, which follows downstream in order to achieve inflow into the combustion zone. In other words, the combustion air is initially supplied to the combustion chamber radially into the intermediate space formed between the casing tube and flame tube and is subsequently deflected so as to provide an axial inflow to the combustion chamber.

In the intermediate space, a circumferential or rotating flow takes place around the flame tube, which is usually cylindrical, so that stagnation points and wake depressions occur with respect to the pressure distribution and flow distribution of the combustion air. When the flow is sharply deflected in addition in the manner described above under such inhomogeneous mass flow distribution, this inhomogeneity remains. This results in uneven cooling of downstream component parts and instability in the combustion zone owing to the fluctuating proportion of air.

SUMMARY OF THE INVENTION

It is the object of the invention to provide a combustion chamber housing and a gas turbine outfitted therewith which ensures a more uniform distribution of the inflowing air around the flame tube.

In accordance with an aspect of the present invention, this object is met by a combustion chamber housing, particularly for a gas turbine, that has a preferably cylindrical flame tube and a preferably cylindrical casing tube or baffle, which receives and surrounds the flame tube and which has a plurality of openings in its wall through which compressed air (cooling and combustion air) outwardly streaming upon the casing tube can penetrate radially into a preferably cylindrical intermediate space formed between the casing tube and the flame tube. In accordance with this aspect, the combustion chamber housing has a plurality of guide ribs, which are arranged in the intermediate space so as to be distributed around the circumference of the two tubes (flame tube and casing tube) and which extend in each instance radially between the casing tube and flame tube and parallel to and along a longitudinal direction of the casing tube and flame tube so that the intermediate space is divided by the guide ribs into a plurality of longitudinal channels which preferably extend substantially along the entire length of the casing tube provided with openings and which preferably have a circle sector-shaped cross section in each instance.

The guide ribs, which extend transverse to the circulating flow direction of air streaming in during operation, interrupt or impede the flow around the flame tube. In this way, the air flow can be distributed more uniformly and there is less disturbance of the cooling of the flame tube. After being deflected, the cooling and combustion air is channeled, in addition, from a radial to an axial flow so that the air can flow into a downstream combustion zone in a homogeneous manner.

By virtue of the optimized inflow of air, a particularly homogeneous fuel-air mixture can be formed in a combustion chamber of a gas turbine, which is formed with the combustion chamber housing according to the invention, so that the flame remains in the center of the combustion chamber in a stable manner during the combustion process. Skewing or fluctuation of the flame would cause a local temperature rise in the surrounding component parts and, therefore, cause a possible overstressing, which is prevented by the guide ribs.

As a result, irregularities in the supply of air are minimized through the use of the combustion chamber housing according to the aspect of invention in a combustion chamber of a gas turbine so that unrestricted operation of the combustion chamber can be carried out at maximum design temperature.

According to an aspect of the invention, the guide ribs are preferably arranged at the casing tube. Further, every guide rib preferably extends radially such that a gap is formed between guide rib and flame tube.

The gap is advantageous for preventing possible warping or stresses resulting from different material properties and thermal expansion coefficient characteristics. Transverse flows occurring through the gaps can be ignored because the flow always radially outwardly contacts the side (inner circumference of the casing tube) on which the flow guide ribs are also arranged.

According to an aspect of the invention, the guide ribs are preferably strip-shaped, their respective width extending radially and their respective length extending axially or in a longitudinal direction of the casing tube and flame tube. The thickness of the respective guide ribs is preferably about 3 mm.

According to an aspect of the invention, the guide ribs and the openings formed in the wall of the casing tube are preferably arranged such that the guide ribs do not close any of the openings. This advantageously ensures an optimal and unimpeded radial inflow of air into the intermediate space.

According to a preferred embodiment of the invention, the quantity of guide ribs provided in the intermediate space is exactly eight, and all of the guide ribs are constructed identically.

According to an aspect of the invention, the guide ribs are preferably arranged at different circumferential angular distances from one another in the intermediate space. The angular distance preferably varies within a range of from about 28 degrees to about 126 degrees.

According to an aspect of the invention, the guide ribs preferably have a first group of guide ribs and a second group of guide ribs, the first group of guide ribs being arranged with respect to their mutual circumferential angular distance in a predetermined first arrangement pattern, and the second group of guide ribs being arranged with respect to their mutual circumferential angular distance in a second arrangement pattern that mirrors the first arrangement pattern at an axis of symmetry of the flame tube. The axis of symmetry preferably extends through the center of the flame tube viewed in cross section.

According to a second aspect of the invention, there is provided a gas turbine with a combustion chamber housing according to one or more or all of the embodiments of the invention described above in any conceivable combination.

The invention also expressly extends to embodiment forms which are not given by combinations of features from explicit references of the claims so that the disclosed features of the invention can be combined with one another in any way insofar as technically meaningful.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described in more detail with reference to a preferred embodiment form and the accompanying figures. In the drawings:

FIG. 1 is a perspective view, partially broken away, of a combustion chamber housing of a combustion chamber of a gas turbine according to an exemplary embodiment of the invention;

FIG. 2 is a front view of the combustion chamber housing of FIG. 1 but with the flame tube omitted;

FIG. 3 is a sectional view of the combustion chamber housing of FIG. 1 viewed along a line A-A in FIG. 2;

FIG. 4 includes two cross-sectional views illustrating a comparison of the air flow distributions and pressure distributions in the combustion chamber housing of FIG. 1 with and without guide ribs.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

A gas turbine 1 (not shown in its entirety) with a combustion chamber housing 10 according to an embodiment of the invention will now be described referring to FIGS. 1 to 4.

The combustion chamber housing 10 of the gas turbine 1 has a cylindrical flame tube 20 and a cylindrical casing tube or baffle 30, which receives and surrounds the flame tube 20 and which has a plurality of openings 31 uniformly distributed around the circumference in its wall through which compressed air (cooling and combustion air), outwardly streaming upon the casing tube 30 through a compressor (not shown) of the gas turbine 1, can penetrate radially into a cylindrical intermediate space 40 formed between the casing tube 30 and the flame tube 20.

A plurality of (in the illustrated embodiment precisely eight) identical guide ribs 50 are arranged in the intermediate space 40 so as to be distributed around the circumference of the two tubes (flame tube 20 and casing tube 30) and extend in each instance radially between the casing tube 30 and the flame tube 20 and parallel to and along a longitudinal direction LR of the casing tube 30 and the flame tube 20 so that the intermediate space 40 is divided by the guide ribs 50 into a plurality of longitudinal channels 41, which extend substantially along the entire length of the casing tube 30 provided with openings 31 and which have a circle sector-shaped cross section in each instance.

The guide ribs 50 reliably prevent a circumferential flow component or a flow component rotating around the flame tube 20 in the air flowing in radially via the openings 31 during operation in the intermediate space 40. In this way, the air flow can be distributed more uniformly around the flame tube 20, improving the cooling of the flame tube 20. In addition, after being deflected (by impingement on the flame tube 20), the air is guided into the longitudinal channels 21 so as to be channeled from radial to axial flow so that it can flow into a downstream combustion zone (not shown) in a homogeneous manner.

The guide ribs 50 are arranged (e.g., welded on) at the inner circumference of the casing tube 30. Every guide rib 50 extends radially such that a gap S is formed between guide rib 50 and flame tube 20. The radial width of the gap S is so dimensioned that various temperature-related expansions of the material of the flame tube 20, casing tube 30 and guide ribs 50 during operation of the gas turbine 1 can be compensated for without the guide ribs 50 pressing on the flame tube 20.

The guide ribs 50 are formed in the manner of sheet metal strips, their respective widths extending radially and their respective lengths extending axially or in longitudinal direction LR of the casing tube 30 and flame tube 20. The thickness of the respective guide ribs 50 is about 3 mm.

As can be seen particularly from FIG. 3 (left-hand side of FIG. 3), the guide ribs 50 and the openings 31 formed in the wall of the casing tube 30 are arranged in such a way that the guide ribs 50 do not close any of the openings 31.

As can be seen particularly from FIGS. 1 and 2, the guide ribs 50 are arranged at different circumferential angular distances from one another in the intermediate space 40.

In this connection, the guide ribs 50 have a first group of guide ribs 50 (arranged on the left-hand side of an axis of symmetry Y of the flame tube 20 in FIG. 2) and a second group of guide ribs 50 (arranged on the right-hand side of the axis of symmetry Y in FIG. 2). According to the depicted embodiment of the invention, the first group of guide ribs 50 is arranged with respect to their mutual circumferential angular distance in a predetermined first arrangement pattern, and the second group of guide ribs 50 is arranged with respect to their mutual circumferential angular distance in a second arrangement pattern, which mirrors the first arrangement pattern at the axis of symmetry Y.

According to the embodiment of the invention shown in FIG. 2, the predetermined first arrangement pattern of the first group of guide ribs 50 is defined by the following angular dimensions: a =27 degrees, b=1.8 degrees, c=34.2 degrees, and d=59.4 degrees. The second arrangement pattern of the second group of guide ribs 50 is defined by the following angular dimensions: a′=27 degrees, b′=1.8 degrees, c′=34.2 degrees, and d′=59.4 degrees.

In other words, in each group of guide ribs 50 according to FIG. 2 there is a combination of angular distances between the guide ribs 50 of 28.2 degrees, 32.4 degrees and 25.2 degrees, and the two groups of guide ribs 50 have an angular distance of 61.2 degrees (at bottom in FIGS. 2) and 126 degrees (at top in FIG. 2).

According to alternative embodiments of the invention, which are not depicted, the first arrangement pattern and second arrangement pattern could also be completely different. For example, the specific implementation of the first arrangement pattern and second arrangement pattern and of the respective angular spacing of the guide ribs 50 can depend, for example, on the design characteristics of the gas turbine 1 and can be adapted accordingly based on the specific flow conditions occurring therein.

FIG. 4 shows two cross-sectional views illustrating a comparison of the air flow distributions and pressure distributions in the combustion chamber housing 10. The combustion chamber housing depicted at top in FIG. 4 is formed without guide ribs 50, and the combustion chamber housing depicted at bottom in FIG. 4, according to the invention, is formed with guide ribs 50.

As can be seen from the upper part of FIG. 4, inhomogeneous air flow conditions and pressure conditions occur without guide ribs 50 during operation of the gas turbine 1 because of the circumferential flow around the flame tube 20 in the intermediate space 40.

As can be seen from the bottom part of FIG. 4, guide ribs 50 extending transverse to the circulating flow direction of the in-flowing air bring about substantially homogeneous air flow conditions and pressure conditions during operation of the gas turbine 1 because they impede the circumferential flow around the flame tube 20 in the intermediate space 40. In this way, the in-flowing air can be distributed uniformly around the flame tube 20 and the cooling of the flame tube 20 is improved. After being deflected, the air is channeled, in addition, from radial to axial flow, so that it can flow into the downstream combustion zone in a homogeneous manner.

Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto. 

1-10. (canceled)
 11. A combustion chamber housing (10) of a gas turbine (1), the combustion chamber housing (10) comprising: a flame tube (20); a casing tube (30) surrounding the flame tube (20), the casing tube having a wall and a plurality of openings (31) in the wall through which air outwardly streaming upon the casing tube (30) can penetrate radially into an intermediate space (40) formed between the casing tube (30) and the flame tube (20); and a plurality of flow guide ribs (50) arranged in the intermediate space (40) so as to be distributed around the circumference of the flame tube (20) and the casing tube (30), the plurality of flow guide ribs (50) arranged radially between the casing tube (30) and flame tube (20), and each of the plurality of flow guide ribs (50) extending parallel to a longitudinal direction (LR) of the casing tube (30) and flame tube (20), such that the plurality of flow guide ribs (50) are welded to the casing tube (30), wherein a gap (S) is formed relative to the flame tube (20) at least in an idle condition of the gas turbine (1) so that the intermediate space (40) is divided by the flow guide ribs (50) into a plurality of longitudinal channels (41).
 12. The combustion chamber housing (10) according to claim 11, wherein the flow guide ribs (50) are strip-shaped.
 13. The combustion chamber housing (10) according to claim 12, wherein the flow guide ribs (50) have a thickness of 3 mm.
 14. The combustion chamber housing (10) according to claim 11, wherein the flow guide ribs (50) and the openings (31) formed in the wall of the casing tube (30) are arranged such that the flow guide ribs (50) do not close any of the openings (31).
 15. The combustion chamber housing (10) according to claim 11, wherein the plurality of flow guide ribs (50) consists of eight identical flow guide ribs (50).
 16. The combustion chamber housing (10) according to claim 11, wherein the flow guide ribs (50) are arranged at different circumferential angular distances from one another in the intermediate space (40).
 17. The combustion chamber housing (10) according to claim 11, wherein the flow guide ribs (50) have a first group of flow guide ribs (50) and a second group of flow guide ribs (50), wherein the first group of flow guide ribs (50) is arranged with respect to their mutual circumferential angular distance in a predetermined first arrangement pattern, and wherein the second group of flow guide ribs (50) is arranged with respect to their mutual circumferential angular distance in a second arrangement pattern which mirrors the first arrangement pattern in relation to an axis of symmetry (Y) of the flame tube (20).
 18. A gas turbine (1) with a combustion chamber housing (10) according to claim
 11. 